In PvP, most physical damage characters carry an elemental damage weapon for use against Warriors (who often have less armor against elemental damage). This stance can be quite dangerous to use since, upon seeing it used, attackers can simply swap weapons.

Bug.If you use a skill or combination of skills and effects that, after subtraction of the penalty from Physical Resistance, still grants +26 or more armor rating against elemental damage, Physical Resistance's armor penalty does not function. See also armor calculation.